The National Weather Service issued a high fire danger alert for Cobb County and other counties in the region on Tuesday, March 19, due to expected low relative humidity this afternoon and into the evening.
What is in the statement?
The statement gives the following details:
HIGH FIRE DANGER CONDITIONS THIS AFTERNOON INTO THE EVENING FOR
NORTH AND CENTRAL GEORGIA DUE TO LOW RELATIVE HUMIDITIES…
Relative Humidities of 25 percent or less can be expected for
4 or more hours this afternoon into the evening. Northwest winds
will switch to the west a little before noon with speeds ranging
8 to 12 MPH.
With dry fuels, high fire danger conditions can be expected.
Please refer to your local burn permitting authorities
whether you may burn outdoors. If you do burn outside,
use extreme caution.
Why does low relative humidity increase the danger of fire?
The National Park Service published the following explanation of why low relative humidity increases the danger of fires:
“Relative humidity is important because dead forest fuels and the air are always exchanging moisture. Low humidity takes moisture from the fuels, and fuels in turn, take moisture from the air when the humidity is high.
“Light fuels, such as grass and pine needles, gain and lose moisture quickly with changes in relative humidity. When the RH drops, fire behavior increases because these fine fuels become drier.
“Heavy fuels, on the other hand, respond to humidity changes more slowly. To see significant changes in heavy fuel moisture, there must be significant moisture, usually from more than a single storm.”
What counties are affected?
The following counties are included in the hazardous weather outlook:
Baldwin, Banks, Barrow, Bartow, Bibb, Bleckley, Butts, Carroll, Catoosa, Chattooga, Chattahoochee, Cherokee, Clarke, Clayton, Cobb, Coweta, Crawford, Crisp, Dade, Dawson, DeKalb, Dodge, Dooly, Douglas, Emanuel, Fannin,…
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